More particularly, but not exclusively, the system of the invention is intended for maintaining a set of solar panels in a folded position, the solar panels being fitted to spacecraft, such as artificial satellites, in particular. Thus, when in the folded position, the elements constitute a zig-zag stack, whereas when in the deployed position, after the retaining system has been withdrawn, the said elements are in end-to-end alignment with one another and the element closest to the structure is hinged thereto.
While a spacecraft is being launched by rocket or by space shuttle, these elements (which may be constituted by several square meters of solar panels) must be folded close together and pressed against the structure of said spacecraft and they must be maintained in that position throughout the launch phase and while being put into orbit.
Suitable systems are used to keep the elements in the folded position and to allow the elements to be deployed by remote control from Earth.
In general, such maintaining systems comprise:
a retaining member passing perpendicularly through said elements in the folded position, with a first end of the retaining member being connected to the structure of the spacecraft while its other end bears against the outermost element of said set;
means for locking the retaining member in the folded position of said elements; and
control means for unlocking said locking means and releasing said retaining member, thereby enabling said set of elements to pass from the folded position to the deployed position under the action, for example, of springs incorporated in the hinges.
In the embodiment taught by patent Document FR-A-2 443 383, the locking means of the maintaining system comprise, in particular, a locking pin disposed perpendicularly to the retaining member and having one of its ends which is provided with a sloping surface engaging in a lateral notch formed near the first end of the retaining member, which notch is provided with a complementary sloping surface. The retaining member and the locking pin are received in respective bores formed in a housing which is fixed to the structure of the spacecraft. In addition, releasable locking elements are associated with the locking pin to prevent it being withdrawn. When these locking elements are actuated, the locking pin responds to the action of a spring and disengages from the retaining member, thereby releasing it and thus allowing the solar panels to pass to their deployed position.
However, this technical solution is not very satisfactory mechanically and may fail to release the retaining member appropriately. The first end of the retaining member is maintained by the locking means in an asymmetrical manner and this may lead to the retaining member becoming mis-aligned on being released. In addition, contact both between the sloping surfaces of the locking pin and of the retaining member, and between the retaining member and the corresponding bore means that friction is high and runs the risk of preventing the retaining member being released.
An object of the present invention is to remedy these drawbacks and to provide a system for maintaining a set of elements in a folded position, which system includes locking means of a design that guarantees the retaining member is properly released when the locking means are actuated.